1948-1952 Shop Service Manual - - Hudson-Essex-Terraplane Club

ENGINE TUNE-UP 2 -7
Connect one lead of tachometer to the distributor
primary terminal and the other lead to engine for ground,
Figure 9. Adjust carburetor to obtain a smooth idle at 540 to
580 R.P.M. (If car is e quipped with Hydra-Matic Transmission,
set idle at 490-510. Vacuum readings at sea level may
be interpreted generally as follows:
17--21" Steady or with slight fluctuation:
Engine in good condition.
15" Steady: Incorrect ignition timing.
10" Steady: Incorrect Valve timing or
burned valves.
15--21" Fluctuating: Sticking valve s or compression leak.
12--16" Drifting: Carburetor too rich or too lean.
Any number of engine conditions may cause the same
action of the vacuum gauge. Exact cause must be established
by elimination.
TAPPET ADJUSTMENT:
To adjust tappets on six or eight cylinder engines, proceed
as follows:
1. Raise front end of car and place stand jacks under frame
crossmember.
2. Remove the right front wheel.
3. Remove the three headlight wires from terminal block to
permit fender side dust shield removal.
4. Place a support below the hood and remove the top (right
side) hood prop bolt to allow hood prop to re main attached
to fender side shield.
5. Remove the twelve 1/4" - 20" hex bolts on the f e n d e r side
dust shield and remove dust shield down and out under the
fender.
6. From under the fender, reach up and remove the front
tappet cover bolt.
7. Remove the rear tappet cover bolt and the breather pipe.
Remove the rear tappet cover by sliding cover forward and
out.
VALVES AND TAPPETS:
FIGURE 10
Check the valve tappet clearance when engine is at
normal operating temperature, Figure 10.
The intake and exhaust valve clearances are as follows:
All 6 Cylinder 8 Cylinder
Intake .010" .008"
Exhaust .012" .010"
8. Remove the lower breather pipe bracket at engine rear end
plate and remove breather pipe.
9. Adjust tappets.
After tappet adjustment has been completed reInstall parts.
NOTE: Use care when tightening the rear tappet cover and
breather pipe attaching screw on eight cylinder engines, so
breather pipe will not bottom against valve cover inner
baffle and restrict ventilator. Tighten to 3 pounds torque.